How a Chinese fossil discovery is rewriting the history of life on Earth

How a Chinese fossil discovery is rewriting the history of life on Earth
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Paleontologists are having a field day over a recently discovered treasure fish fossils it could reset our understanding of human evolution. The finds not only contain the world’s oldest teeth, but also strengthen evidence for the formation of jaws and limbs. In fact, these discoveries may push our understanding of humans’ earliest animal ancestors back nearly 10 million years.

The international team responsible for these remarkable findings was led by Zhu Min of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing, China, and is detailed in a quartet of papers published Wednesday in the journal Nature.

The fossils date back to 436 to 439 million years ago, a period known as the Silurian, when the Earth experienced some of its events. dramatic events (e.g., the development of the ozone layer) had a major impact on the evolution of life. At the end of the Silurian, jawed fishes began to appear; the advantage of jaws is that it makes better hunters, which allows such fish to better pass on their genes. Indeed, having a chin is quite an evolutionary advantage.

Most of the creatures in the oceans were quite delicate, which means they are less likely to survive in the fossil record. Generally, scientists have relied on scraps and stray fossils of such creatures to form theories about how life arose on Earth during this time, but these new discoveries shed more light on what life was like almost half a billion years ago.

It was discovered near the village of Lianghe in Hunan Province. T. vividus it looked like an ice cream cone with a massive bony shield around its head.

“The new fossils change everything. Now we know how big they were, what they looked like, how they evolved over time,” he said. Reuters. In terms of size, most of these fossils were quite small – but they had a big impact.

one paper More than 1,000 specimens of extinct spiny shark-like fish were examined Fanjingshania is updated, named so because it was found near Mount Fanjinshan. It may be the oldest jawed ancestor of humans, pushing back the previous record by nearly 20 million years.

else paper describes Tujiaaspis vividus, an extinct jawless fish named after the Tujia people, an ethnic minority in China. It was discovered near the village of Lianghe in Hunan Province. T. vividus it looked like an ice cream cone with a massive bony shield around its head, calling it a galeaspid. What’s surprising about this finding is how intact the sample is compared to previous findings.

“The anatomy of galeaspids has remained a mystery since they were first discovered more than half a century ago,” said Gai Zhikun, lead author of the study and professor at IVPP. statement. “You have thousands of fossils known from China and Vietnam, but almost all of them are heads – nothing is known about the rest of their bodies to this day.”

These fossils”fin-layer theory,” which describes how fish developed the diverging ends that eventually became legs. In other words, it’s some of the earliest and strongest evidence for the leading theory of how humans ended up with our limbs.

Then there is a paper describing two new species. First Xiushanosteus mirabilis, a small placoderm, a type of armored jawed fish. The other one Shenacanthus vermiformis, an early shark relative. But unlike sharks (which have small scales) S. vermiformis armored with plates covering its body.

“Just 20 years ago, sharks were still believed in [were] primitive and other jawed fish evolved from a shark-like archetype. Now, with the discovery of Shenacanthus, we can finally confirm that the opposite is true,” said Zhu You’an, associate research professor at IVPP and lead author of the study. statement. Both discoveries could change the timeline of when jawed vertebrates first appeared.

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The last one paper describes the least complete fossil specimen of the four, with only 23 teeth—still enough information to identify the earliest direct evidence for jawed vertebrates like us. It is called fish Qianodus duplicis, found in Guizhou Province, had the oldest teeth of any previously known animal. His mouth was full of double rows of fangs, and like many early drafts, the teeth don’t actually look like the pearly whites we think of. It’s a spiky drop, more like the back of the blue shell in Mario Kart.

Nevertheless, this tooth discovery pushes back the evolutionary history of teeth by about 14 million years. This means that during the Silurian period (about 439 million years ago) there was much more activity than we thought.

It may seem strange to think, but there was a point in the evolutionary timeline where there were no teeth. The same goes for eyes, brains, and even anuses. Each of these anatomical features has evolved over millions of years as a result of natural selection. While there are many gaps in the fossil record, they’re being filled in all the time, and a trove of recently published results provide fascinating insight into where we got our teeth, jaws, limbs, and indeed, our human bodies.

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